title: Pachymetry changes during corneal crosslinking: effect of closed eyelids and hypotonic riboflavin solution.
abstract: OBJECTIVE
  To evaluate pachymetry changes during standard corneal crosslinking (CXL) and the effect of closed eyelids and hypotonic riboflavin in thin corneas.
  
  
  METHODS
  Department of Ophthalmology, Medical University of Vienna, Vienna, Austria.
  
  
  METHODS
  Comparative case series.
  
  
  METHODS
  Eyes with progressive keratoconus had standard epithelium-off CXL. In Group 1, a lid speculum was used during the procedure. In Group 2, the lids were closed during saturation with riboflavin. In Group 3, hypotonic riboflavin was used. In Groups 1 and 2, swelling was performed with hypotonic riboflavin if pachymetry was less than 400 μm. The thinnest corneal pachymetry (TCP) was measured preoperatively, after epithelium removal, and every 10 minutes thereafter.
  
  
  RESULTS
  Thirty-five eyes were evaluated. After epithelium removal, the mean TCP was 401 μm ± 15 (SD), 411 ± 35 μm, and 400 ± 24 in Groups 1, 2, and 3, respectively. In Group 1, the TCP decreased to 355 ± 23 μm after the first 30 minutes. In Group 2, the TCP remained stable throughout the saturation phase. In Group 3, the TCP increased. During the irradiation phase, a reduction in pachymetry occurred in all groups. Thinnest corneal pachymetry readings less than 400 μm were found in all eyes irrespective of the protocol.
  
  
  CONCLUSIONS
  Corneal desiccation with riboflavin with 20% dextran can be avoided when removing the lid speculum during saturation with riboflavin. The use of hypotonic riboflavin solution increased corneal pachymetry, although the final TCP remained unchanged. To increase endothelial safety, new isooncotic solutions are needed.
authors.affiliation: Department of Ophthalmology, Medical University of Vienna, Vienna, Austria. gerald.schmidinger@meduniwien.ac.at
authors.forename: Gerald
authors.initials: G
authors.lastname: Schmidinger
authors.forename: Mojtaba
authors.initials: M
authors.lastname: Pachala
authors.forename: Franz
authors.initials: F
authors.lastname: Prager
mesh_terms: D000328:Adult; D003094:Collagen / Q000378:metabolism; D003315:Cornea / Q000473:pathology*; D063171:Corneal Pachymetry; D003319:Corneal Stroma / Q000378:metabolism; D003432:Cross-Linking Reagents / Q000627:therapeutic use*; D004108:Dilatation, Pathologic / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D005143:Eyelids / Q000502:physiology*; D005260:Female; D006801:Humans; D007038:Hypotonic Solutions; D007640:Keratoconus / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D008297:Male; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D011379:Prognosis; D011446:Prospective Studies; D012256:Riboflavin / Q000627:therapeutic use*; D014792:Visual Acuity / Q000502:physiology
chemical_list: D003432:Cross-Linking Reagents; D007038:Hypotonic Solutions; D017319:Photosensitizing Agents; D003094:Collagen; D012256:Riboflavin